Expressions of the γ2 chain of laminin-5 and secreted protein acidic and rich in cysteine in esophageal squamous cell carcinoma and their relation to prognosis

Previous studies have shown that the expressions of the γ2 chain of laminin-5 and secreted protein acidic and rich in cysteine (SPARC) play important roles in oncogenesis and the development of carcinoma. To assess the expressions of laminin-5 γ2 chain and SPARC in esophageal squamous cell carcinoma (SCC), and to clarify the prognostic significance of the expressions of laminin-5 γ2 chain and SPARC in esophageal SCC, we detected the expressions of laminin-5 γ2 chain and SPARC in cancer tissue and corresponding normal mucosa from 116 patients with advanced (stages II-IV) esophageal SCC using the tissue microarray-based immunohistochemistry and analyzed the correlation of the expressions with clinicopathologic characteristics and survival. We found that in normal esophageal tissues, laminin-5 γ2 chain was expressed in the basement membrane, whereas in esophageal SCC tissues, laminin-5 γ2 chain was expressed in the cytoplasm of carcinoma cells, with a positive rate of 72.4%. SPARC was not detected in normal esophageal mucosa, but was expressed in stromal fibroblasts in 84.6% of esophageal SCC cases and in cancer cells in 7.8% of esophageal SCC cases. There was a significant correlation between laminin-5 γ2 chain and stromal SPARC expression in esophageal SCC (Spearman's rho=0.423, P<0.001). The expressions of both laminin-5 γ2 chain and stromal SPARC were correlated with survival (P=0.032 and P=0.034, respectively). In stage-II esophageal SCC, the expression of laminin-5 γ2 chain was significantly correlated with survival (P=0.023), while the expression of SPARC was not significantly correlated with survival (P=0.154). Patients with elevated levels of laminin-5 γ2 chain and SPARC expressions had a poorer prognosis than did those lacking elevated levels of laminin-5 γ2 chain expression and/or elevated levels of SPARC expression (P=0.001). In stage-II esophageal SCC, patients with elevated levels of laminin-5 γ2 chain and SPARC expressions had a poorer prognosis (P<0.001). These results suggest that laminin-5 γ2 chain and SPARC may play roles in the progression of esophageal SCC and their simultaneous expression is correlated with poorer prognosis, especially in patients with stage-II SCC.